Influence of gender and degree of obesity on the left ventricular adaptation to pressure overload in stage I hypertension.

To examine the association between ambulatory blood pressure (BP) and left ventricular (LV) mass in the initial phase of hypertension, 499, 18 to 45 year old stage I hypertensive subjects (377 men and 122 women) were studied with two 24-hour ambulatory BP monitorings, echocardiography, and 24-hour urine collection for catecholamines assessment. Mean age was 33±9 years and office BP was mmHg. LV hypertrophy was present in 4.2% of men and 12.3% of women (p=.001). Relative wall thickness was greater in women (p=.05). When the subjects were divided into quartiles of increasing daytime systolic BP, in men no LV parameter differed across the quartiles of ambulatory BP. Instead, in women LV mass (p=.009), posterior wall thickness (p=.02) and interventricular septum thickness (p=.03) showed a clear tendency to the increase with increasing levels of systolic BP, so that the women of the highest BP quartile had a similar LV mass and a greater interventricular septum thickness (p<.05) than the men in the corresponding quartile. In a multiple regression analysis, daytime systolic BP explained only a small fraction of the variance in LV indexes in men, while in women daytime systolic BP was a main determinant of LV mass and posterior wall and septal thicknesses. Body mass index explained most of the variance in all dimensional parameters in men. Also in women body mass index was an important predictor of LV mass and diameter, but was unrelated to posterior wall and septal thicknesses. Epinephrine and norepinphrine output was unrelated to echocardiographic parameters. In conclusion, daytime systolic BP is the most important predictor of LV mass and geometry in premenopausal women with borderline to mild hypertension, while in men LV dimensional indexes are chiefly explained by degree of obesity.